#!/usr/bin/env python3

#
# This file is part of LiteX-Boards.
#
# Copyright (c) 2018-2019 Rohit Singh <rohit@rohitksingh.in>
# Copyright (c) 2019-2020 Florent Kermarrec <florent@enjoy-digital.fr>
# SPDX-License-Identifier: BSD-2-Clause

import os

from migen import *

from litex_boards.platforms import nereid

from litex.soc.interconnect.csr import *
from litex.soc.integration.soc_core import *
from litex.soc.integration.builder import *

from litex.soc.cores.clock import *

from litedram.modules import MT8KTF51264
from litedram.phy import s7ddrphy

from litepcie.phy.s7pciephy import S7PCIEPHY
from litepcie.software import generate_litepcie_software

# CRG ----------------------------------------------------------------------------------------------

class CRG(Module):
    def __init__(self, platform, sys_clk_freq):
        self.rst = Signal()
        self.clock_domains.cd_sys    = ClockDomain()
        self.clock_domains.cd_sys4x  = ClockDomain(reset_less=True)
        self.clock_domains.cd_idelay = ClockDomain()

        # Clk/Rst
        clk100 = platform.request("clk100")

        # PLL
        self.submodules.pll = pll = S7PLL()
        self.comb += pll.reset.eq(self.rst)
        pll.register_clkin(clk100, 100e6)
        pll.create_clkout(self.cd_sys,    sys_clk_freq)
        pll.create_clkout(self.cd_sys4x,  4*sys_clk_freq)
        pll.create_clkout(self.cd_idelay, 200e6)
        platform.add_false_path_constraints(self.cd_sys.clk, pll.clkin) # Ignore sys_clk to pll.clkin path created by SoC's rst.

        self.submodules.idelayctrl = S7IDELAYCTRL(self.cd_idelay)

# BaseSoC -----------------------------------------------------------------------------------------

class BaseSoC(SoCCore):
    def __init__(self, sys_clk_freq=int(100e6), with_pcie=False, **kwargs):
        platform = nereid.Platform()

        # SoCCore ----------------------------------------------------------------------------------
        SoCCore.__init__(self, platform, sys_clk_freq,
            ident = "LiteX SoC on Nereid",
            **kwargs)

        # CRG --------------------------------------------------------------------------------------
        self.submodules.crg = CRG(platform, sys_clk_freq)

        # DDR3 SDRAM -------------------------------------------------------------------------------
        if not self.integrated_main_ram_size:
            self.submodules.ddrphy = s7ddrphy.K7DDRPHY(platform.request("ddram"),
                memtype          = "DDR3",
                nphases          = 4,
                sys_clk_freq     = sys_clk_freq,
                iodelay_clk_freq = 200e6)
            self.add_sdram("sdram",
                phy           = self.ddrphy,
                module        = MT8KTF51264(sys_clk_freq, "1:4", speedgrade="800"),
                size          = 0x40000000,
                l2_cache_size = kwargs.get("l2_size", 8192)
            )

        # PCIe -------------------------------------------------------------------------------------
        if with_pcie:
            self.submodules.pcie_phy = S7PCIEPHY(platform, platform.request("pcie_x4"),
                data_width = 128,
                bar0_size  = 0x20000)
            self.add_pcie(phy=self.pcie_phy, ndmas=1)

# Build --------------------------------------------------------------------------------------------

def main():
    from litex.soc.integration.soc import LiteXSoCArgumentParser
    parser = LiteXSoCArgumentParser(description="LiteX SoC on Nereid")
    target_group = parser.add_argument_group(title="Target options")
    target_group.add_argument("--build",        action="store_true", help="Build bitstream.")
    target_group.add_argument("--load",         action="store_true", help="Load bitstream.")
    target_group.add_argument("--sys-clk-freq", default=100e6,       help="System clock frequency.")
    target_group.add_argument("--with-pcie",    action="store_true", help="Enable PCIe support.")
    target_group.add_argument("--driver",       action="store_true", help="Generate PCIe driver.")
    builder_args(parser)
    soc_core_args(parser)
    args = parser.parse_args()

    soc = BaseSoC(
         sys_clk_freq = int(float(args.sys_clk_freq)),
         with_pcie    = args.with_pcie,
         **soc_core_argdict(args)
    )
    builder = Builder(soc, **builder_argdict(args))
    builder.build(run=args.build)

    if args.driver:
        generate_litepcie_software(soc, os.path.join(builder.output_dir, "driver"))

    if args.load:
        prog = soc.platform.create_programmer()
        prog.load_bitstream(builder.get_bitstream_filename(mode="sram"))

if __name__ == "__main__":
    main()